* {
    margin: 0;
    padding: 0;
}
.w{
    width: 1200px;
    margin: auto;
}
.header{
    height: 45px;
    background-color: #212b5c;
    margin: 30px;
}
.logo{
    float: left;
    width: 131px;
    height: 45px;
    background-color: green;
}
li{
    list-style: none;
}
.nav{
    float: left;
    margin-left: 50px;
    width: 600px;
    overflow: hidden;
}
.nav ul li{
    float: left;
}
.nav ul li a{
    display: block;
    width: 70px;
    padding: 0 30px;
    line-height: 40px;
    font-style: normal;
    text-decoration: none;
    font-weight: 600;
    color: white;
}
.nav ul li a:hover{
border-bottom: 5px solid white;
}
.search{
    float: left;
    margin-left: 30px;
    width: 300px;
    height: 45px;
}
.search input{
    float: left;
    width: 240px;
    height: 42px;
    border: 1px solid #212b5c;
    border-right: 0;
}
.search button{
    float: left;
    width: 55px;
    height: 44px;
    border: 0;
    background-image: url(./img/搜索.png);
}
.nav ul li ul{
    display: block;
    position: absolute;
}
.nav ul li ul li{
    font: left;
    height: 38px;
}
.nav ul li ul li a{
    float: left;
    font-size: 16px;
    background-color: pink;
    border-right: none;
    border-top: 1px dotted #ccc;
    border-color: blue;
    padding-top: 0;
    height: 380px;
}
.nav ul li ul li a:hover{
    display: block;
    float: left;
}
.text{
    opacity: 0;
}
.nav:hover .text{
    opacity: 1;
}
.bannar{
    height: 430px;
    background-color: skyblue;
}